New Topological Insulator ConfirmedCategory: Science & Technology
Posted: August 1, 2014 09:16AM
They say one should not judge a book by its cover, and that is definitely true of some materials as well. Topological insulators (TIs) are interesting materials that will conduct electrons across their surfaces, but not through their insulating volumes, which leads to some curious electrical properties. It has recently been confirmed by researchers at Ecole Polytechnique Fédérale de Lausanne, the Paul Scherrer Institute, and the Chinese Academy of Science that one material hoped to be TI is one, but with some very special properties.
Samarium hexaboride (SmB6) has been theorized to be a TI for some time, but the reasons behind it are slightly different from others. The bulk of SmB6 is an insulator due to the Kondo effect, which causes electrons to scatter in a material due to temperature. It also has the effect of protecting electron currents from being disturbed by irregularities in a material. This means that a topological Kondo insulator would be very robust and efficient, even compared to other TIs that can conduct electricity on their surfaces with minimal resistance. To confirm SmB6 is a topological insulator, the researchers fired photons at it with enough energy to knock electrons off of it. These electrons were then measured to provide information on the TI.
One of the reasons topological insulators are of such interest is that electrons traveling on their surface preserve their spin, an intrinsic characteristic giving electrons their magnetic properties. The hope is that computers could one day be built that operate on electronic spin, instead of electronic charge, and TIs will likely help make that possible.